A NEW BRANCHIATE OLIGOCHATE. 337 
ment 11 are totally absent, nor are they replaced by penial 
sete. 
- Between Segments 11/12 are the oviducal pores. On the 
12th segment the first pair of nephridiopores are to be seen, as 
already mentioned. 
With regard to the internal parts of the generative system, 
the position of the testes and ovaries has been already men- 
tioned. 
The sperm-sacs are very greatly developed ; they extend 
from the 9th to the 17th segment ; they lie dorsally as well as 
on both sides of the intestine. 
The sperm-duct opens by a large funnel on each side into 
the interior of the 10th segment; the sperm-duct is compara- 
tively short, and after a few windings opens, as shown in fig. 12, 
into a straightish tube which leads to the exterior. In that 
fignre the relations of the different parts of the whole efferent 
apparatus are shown; the whole apparatus differs in many 
points from the corresponding organs of other Tubificidee. There 
is a large sac (fig. 1, A?¢.) on each side of the body in the 11th 
segment ; this has a somewhat oval contour, and presents the 
histological structure indicated in the figure. The lumen is nar- 
row, and lined with a single layer of epithelial celis, which has 
been hardly at all stained by the borax carmine; they are clear 
in appearance, and their nuclei are pushed back to the base of 
the cell: this seems to indicate that the cells are in full secre- 
tory activity. Outside of this epithelial lining is a layer of 
muscular fibres about equal in thickness to the epithelium, the 
fibres of which are mostly arranged in a circular direction. 
This muscular layer is covered by a very thick layer of cells, 
five or six deep, which seem to represent a very much thickened 
peritoneal coating. 
This sac has a structure which evidently corresponds to that 
of the atrium of other Oligocheta, particularly of Rhynchel- 
mis! and Moniligaster,? and more particularly of the latter ; 
1 Vespovsky, “ Anatomische Studien an Rynchelmis Limosella, &c.,” 
‘ Zeit. wiss. Zool.,’ Bd. xxvii, Taf. xxiv, fig. 1. 
2 BepparD, “ On the Structure of Three New Species of Earthworms, &c.,” 
Quart, Journ. Mier. Sci.,’ vol. xxix, pl. xu, fig. 11. 
